Conceptual Issues in Evolutionary Biology - Biolozi.net

Moral Philosophy as Applied Science 563
most readily acquired against snakes, spiders, high places, running water, tight enclosures,
and other ancient perils of mankind for which epigenetic rules can be expected
to evolve through natural selection. In contrast, phobias very rarely appear in response
to automobiles, guns, electric sockets, and other truly dangerous objects in modern life,
for which the human species has not yet had time to adapt through genetic change.
Epigenetic rules have also been demonstrated in more complicated forms of mental
development, including language acquisition, predication in logic, and the way
in which objects are ordered and counted during the first steps in mathematical
reasoning. 17
We do not wish to exaggerate the current status of this area of cognitive science. The
understanding of mental development is still rudimentary in comparison with that of
most other aspects of human biology. But enough is known to see the broad outlines
of complex processes. Moreover, new techniques are constantly being developed to explore
the physical basis of mental activity. For example, arousal can be measured by the
degree of alpha wave blockage, allowing comparisons of the impact of different visual
designs. Electroencephalograms of an advanced design are used to monitor momentby-moment
activity over the entire surface of the brain. In a wholly different procedure,
radioactive isotopes and tomography are combined to locate sites of enhanced
metabolic activity. Such probes have revealed the areas of the brain used in specific
mental operations, including the recall of melodies, the visualization of notes on a musical
staff, and silent reading and counting. 18 There seems to be no theoretical reason
why such techniques cannot be improved eventually to address emotions, more complex
reasoning, and decision making. There is similarly no reason why metabolic activity
of the brain cannot be mapped in chimpanzees and other animals as they solve
problems and initiate action, permitting the comparison of mental activity in human
beings with that in lower species.
But what of morality? We have spoken of color perception, phobias, and other less
value-laden forms of cognition. We argue that moral reasoning is likewise molded and
constrained by epigenetic rules. Already biologists and behavioral scientists are moving
directly into that area of human experience producing the dictates of right and wrong.
Consider the avoidance of brother-sister incest, a negative choice made by the great
majority of people around the world. By incest in this case is meant full sexual attraction
and intercourse, and not merely exploratory play among children. When such rare
matings do occur, lowered genetic fitness is the result. The level of homozygosity (a
matching of like genes) in the children is much higher, and they suffer a correspondingly
greater mortality and frequency of crippling syndromes due to the fact that some
of the homozygous paris of genes are defective. Yet this biological cause and effect is
not widely perceived in most societies, especially those with little or no scientific
knowledge of heredity. What causes the avoidance instead is a sensitive period between
birth and approximately six years. When children this age are exposed to each